Ingot stripping apparatus



Oct. 17, 1933. E. GATHMANN 1,931,187

INGO'I STRIPPING APPARATUS Filed June 28, 1952 6 Sheets-Sheet l (IttorOct. 17, 1933.

E. GATHMANN v INGOT STRIPPING APPARATUS Filed June 2s, 19:52

6 Sheets-Sheet 2 Oct. 17, 1933. E. GATHMANN INGOT STRIPPING APPARATUS 6Sheets-Sheet 3 Filed June 28, 1952 m EEF E m E Oct. 17,1933. E. GATHMANNI 1,931,187

- INGOT STRIPPING APPARATUS Filed June 28, 1932 6 Sheets-Sheet 4 Oct.17, 1933.

E. GATHMANN INGOT STRIPPING APPARATUS Filed June 28, 1932 6 Sheets-Sheet6 Patented Oct. 17, 1933 UNITED STATES PATENT OFFICE 54 Claims.

This invention relates to apparatus for stripping ingots from ingotmolds, and more particularly to apparatus for this purpose includingmeans for moving the molds of a jag successively to the strippingposition, for holding the positioned molds against movement during thestripping operation, and for partially ejecting the contained ingotsfrom the molds when the latter are held against movement.

It is well known that the best grades of steel produced at the presenttime are made from big end up ingots, i. e., ingots cast in molds thechambers of which are larger at the top than the bottom thereof. Moldsof this type provide for the extraction of heat from the molten ingotmetal progressively from the bottom toward. the top thereof so as toprevent the formation of pipes in the ingot body and to concentrate theshrinkage cavity and impurities at the extreme upper portion of theingot, so that a minimum amount of metal is lost through cropping.

Because of the greatly superior physical properties of steel cast in bigend up molds as compared to that cast in big end down molds, the

- use of the former kind of mold is increasing steadily, but even atpresent most steel is cast in big end down molds, due to the greaterfacility of handling such molds with the equipment now available in themills.

The usual practice followed in stripping nonsinkhead ingots from big endup molds consists in inverting each mold individually after the ingothas solidified, lifting the mold off the ingot, and then lifting theingot by means of tongs or the like and removing it to the soaking pits.

This old practice of stripping big end up molds is somewhat more timeconsuming and consequently more expensive than the easier process ofstripping big end down molds, which consists merely in lifting the moldsoff the ingots without its being necessary first to invert the molds.This single factor operating in favor of the use of big end down moldsis largely if not entirely responsible for the continued use of suchmolds in spite of the fact that only inferior grades of steel can beproduced therein.

In my copending United States applications Ser. No. 486,463, filedOctober 4, 1930, and Ser. No. 567,281, filed October 6, 1931, I haveshown, described and claimed stripping apparatus which are adaptedparticularly for stripping ingots from big end up molds. Apparatusembodying the present invention includes some'features of theconstructions shown in the copending applications referred to, andfurther includes a novel general arrangement and novel details ofconstruction which make possible a. much more rapid stripping of ingotsthan is possible even with the apparatus disclosed in the copendingapplications referred to.

Generally stated, apparatus in accordance with the present inventionincludes a movable support for moving the molds of a jag successively tostripping position adjacent a stripping device, a mold holding devicemounted for movements into engagement with a mold in stripping positionfor holding the latter against movement during the stripping operation,and automatic control means interconnecting the means for 7 operatingthe movable support, the stripping device, and the mold holding deviceso as to effect operation of certain of the parts automatically toincrease the speed with which a jag of molds may be stripped, and alsoto prevent accidental operation of the parts at the wrong time whichotherwise might result in damage to the apparatus and in costlydelays.Apparatus embodying the invention also includes independently of theinterconnected control means, novel features of construction andarrangement of the mold positioning support, the mold holding device,and the stripping device.

An object of the invention is to provide an apparatus of the characterdescribed including a movable mold support for positioning a mold instripping position, a holding device mounted for movements intoengagement with a positioned mold, a stripping device for effectingpartial ejection of the contained ingot from a positioned mold, andmeans controlling the operation of the mold support, the mold holdingdevice, and the stripping device automatically or semi-automatically inaccordance with a predetermined sequence, and/ or for preventingaccidental operation of certain parts of the apparatus during certainperiods of the operating cycle.

Other objects of the invention are to provide improved means forimparting step by step movements to the mold support for positioningsuccessively the molds of a jag in stripping position; to provide animproved construction of mold holding device, and to provide improvedmeans for operating the stripping device in a manner to cause the latterto exert a predetermined pressure upon an ingot for stripping thelatter, and automatically to exert a greater pressure upon the ingot toassure stripping of the ingot if the latter sticks to the mold to suchan extent as to resist being stripped under the lower predeterminedpressure. Other objects will become apparent from the followingdescription, the appended claims, and the accompanying drawings.

In the drawings:

Figure 1 is a side view, partly in elevation and partly in verticalsection, of apparatus embodying the invention, and Figure 1 is a similarview constituting a continuation or extension of Figure 1;

Figure 2 is a transverse vertical sectional view taken on the line 22 ofFigure 1;

Figure 3 is a transverse vertical sectional view taken on the line 3--3'of Figure 1, and drawn on an enlarged scale;

Figure 4 is a horizontal sectional view taken on the line 44 of Figure3;

Figure 5 is a transverse vertical sectional view of a rack and drivemechanism therefor taken on the line 5-5 of Figure 1, and drawn on anenlarged scale;

Figure 6 is afragmentary top plan view of the drive mechanism shown inFigure 5, a gear case cover being removed;

Figure 7 is a fragmentary plan view of certain switches and operatingmechanism as viewed when looking in the direction of the arrow 7 inFigure 2 and drawn on an enlarged scale;

Figure 8 is a fragmentary plan view of switches and operating mechanismas viewed from the top of Figure 2 and drawn on an enlarged scale;

Figure 9 is an enlarged detail view of switches arranged to be operatedby a stripper plunger;

Figure 10 is a fragmentary vertical sectional view of a hold down screwand mold clamping head drawn on an enlarged scale; and Figure 10 is afragmentary horizontal sectional view taken on the line lo --10 ofFigure 10;

Figure 11 is aview in front elevation of a valve and valve operatingmeans drawn on an enlarged scale;

Figure 12 is a view in front elevation of a modified form of moldengaging head shown as engaging a mold of relatively large size;

Figure 13 is a view similar to Figure 12 but certain parts being shownin section and the head being shown in engagement with a relativelysmall mold;

Figure 14 is a detail view in front elevation of a mold engaging leg;

Figure 15 is a sectional view taken on the line 15-15 of Figure 13;

Figure 16 is a diagrammatic showing of an electrical control circuit fora rack operating motor; 1

Figure 1'7 is a diagrammatic showing of an electrical control circuitfor a hold down screw operating motor;

Figure 18 is a diagrammatic showing of an electrical control circuit fora valve operating motor;

Figure 19 is a diagrammatic showing of an electrical control circuit foranother valve operating motor; and

Figure 20 is a sectional view taken on the line 20-20 of Figure, 2.

The embodiment of the invention shown by way of illustration in theaccompanying drawings includes mold holding apparatus generallydesignated A for holding molds against movement during the strippingoperation, ingot stripping apparatus generally designated B disposed incooperative relationship with the holding apparatus A, and moldpositioning means C for positioning successively the individual molds ofa jag of molds in stripping position relative to the mold holding andingot stripping apparatus A and B. As shown in Figure l, a plurality ofmolds D D D is mounted in spaced relation upon a movable mold support inthe present instance comprising a plurality of coupled cars E arrangedto be moved relative to the mold hold-' ing and ingot strippingapparatus along tracks F. In Figure 1, D represents molds the ingotscontained in which have been partially stripped, D represents a mold instripping position, and D D represent molds which have not beenpositioned in the stripping apparatus and the contained ingots in whichhave not been stripped.

Referring to Figure 2, it will be noted that there are two rows of moldssupported on each car E. Similarly, as will later be described, thereare two holding devices for operating respectively on the molds of eachrow and two stripping devices for operating successively on the molds ofeach row. Inasmuch as the holding and stripping apparatus for operatingin connection with one row of molds is the same as that for operating inconnection with the other row of molds, the following description willrefer specifically only to the row of molds, the holding apparatus, andthe stripping apparatus shown at the right of Figure 2, it beingunderstood that the corure 2 are exactly the same. Similarreferencecharacters are used to designate the corresponding elements of theapparatus shown on each side of the figure, with the exception that thereference characters applied to the elements on the left are primed.

Each of the cars E is formed with a plurality of spaced pads 1 whichserve to assist in the locating of stools 2 each comprising a marginalpart 3 and a horizontal web 4 spaced midway between the upper and lowerfaces of the marginal part 3 to provide a bottom depression 5 and a topdepression 6. As shown in. Figures 1 and 2, the pads 1 are adapted toextend up into the bottom depressions 5 of the stools so as to assist inlocating or centering the latter. The molds are formed on their bottomfaces with marginal seats '7 adapted to rest upon the top faces of themarginal parts 3 of the stools, and with centrally disposed pads 8adapted to extend down into the top depressions 6 of the stools 3, thepads 8 cooperating with the stools to assist in locating the molds inthe desired spaced relation. The stools 2 and their mounting upon thecars E do not per se constitute any part of the present invention and itwill be understood that in practicing the invention the stools may, ifdesired, be omitted and the molds supported directly upon the cars.

The molds shown are of the big end up kind, that is, the ingot-formingchambers thereof are of greater cross sectionat the top than at thebottom, and consequently stripping of the ingot must be efiected in adirection upwardly from the bottom to the top of the mold. The moldsshown are provided with tapered bottom openings 9 which, when the moldsare positioned on the stools as described above, are aligned withopenings 10 in the stool and with openings 11 in the car. Refractory ormetallic closure plugs 12 are seated in the openings 9 of the moldsprior to the teeming of the latter.

Stripper rods 13 are mounted for vertical reciprocation in the openings11 in the car and are provided with heads 14 adapted, when the rods arein their lower positions, to be seated upon the .pads 1 on the car so asto limit the downward responding elements shown in the left ofFigmovement of the stripper rods. The" heads 14 are considerably smallerin diameterthan the openings 10 in the stools and the openings 9 in themold bottoms so as to permit the heads being raised through the openingsand 9 without danger of contacting with the sides of these openings,even though the molds are not centered absolutely accurately withrespect to the stripper rods.

Each stripper rod is formed with a longitudinally extending slot orgroove 15 which is provided with a pair of spaced notches 16. A straightlatch rod 17 is mounted for sliding movements in guides 18-18 formed inthe car, and is provided at its outer end with a handle 19, the innerend of the rod having sliding engagement with the stripper rod 13 in thegroove 15 thereof and being urged constantly to the bottom of the grooveby means of a spring 20.

In operation, assuming the parts thus far described to be in thepositions shown in Figures 1 and 2, and assuming the mold D to be helddown on top of the car E by means to be described later, stripping ofthe ingot in the mold D is effected by raising the stripper rod 13 in amanner later to be described so as to cause the head 14 of the rod tomove upwardly through the openings 10 and 9 -and to engage the closure12 so as to move the ingot upwardly with respect to the mold. When therod 13 has been moved upwardly to such an extent as to bring theuppermost of the notches 16 opposite the latch rod 17, the latter willbe forced into the notch under the urge of the spring 20, therebymaintaining the rod and ingot in their raised positions, after which themold is released by the holding means and may be moved away from thestripping and holding apparatus. Preferably air is allowed to circulateup through the openings 10 and 9 into the mold and thence up through thespace between the mold and the partially stripped ingot in order toeffect solidification of the ingot in accordance with the methoddisclosed and claimed in myv copending application Ser. No. 621,100,filed July 6, 1932. To this end the car is provided with a plurality ofopenings 20 under each stool 2, the arrangement being such that when theingot is partially stripped air will flow up through the openings 20 inthe car, the opening 10 in the stool, the opening 9 in the mold, andthence up through the mold. The nature of the solidification produced bythe flow of air is described in detail in the copending applicationreferred to.

As previously stated, it is necessary to hold the molds down upon thecars when the stripping operation is performed. For accomplishing thispurpose, I provide the mold holding apparatus A previously referred togenerally and shown as including a tower 21 consisting essentially ofbraced vertical members 22 and horizontal top members 23 upon which ispositioned a frame casting 24. The frame 24 is formed with two housings25-25 spaced laterally the same distance as the center to centerdistance of the rows of molds. Captive nuts 26 and 26' are mounted inthe housings 25 and 25' respectively, and each is arranged to operatemeans for engaging the top faces of the molds underneath for holding thelatter against vertical movement during the stripping operation.Referring more specifically to the nut 26 shown at the right of Figure 2and to the associated mechanism, this nut is mounted for rotation inbearings 27 positioned in the housing 25 and is held against upwardmovement by a thrust bearing 28. A worm gear 29 is fitted around andsecured to the outside of the nut 26 and is in mesh with a worm 30 fixedto a shaft 31 which is arranged to be driven by an electric motor 32through the medium of intervening re-- duction gearing 33. The motor isreversible and may be controlled in a manner to be described later so asto drive the worm 30 to operate the nut 26 in either direction ofrotation.

The nut 26 is formed with a vertical interiorly threaded bore whichreceives and cooperates with an exteriorly threaded rod or screw 34which is guided for vertical movements in bearings 35 and 36 in thehousing 25. The screw 34 is formed with a longitudinally extending slotor groove 37 which receives for sliding movements a key or spline 38secured to the bearing 36, the key 38 thus cooperating with the slot inthe screw to prevent rotation of the latter.

At its lower end portion, the screw 34 is formed with a reduced part orneck 39, and, at its extreme lower end, is provided with an enlargement40 disposed in a recess 41 .of a clamping head 42 mounted on the screwfor limited vertical movements relative thereto. Split plate halves 4343conjointly formed with a centrally disposed inwardly directedoverhanging part or flange 44 defining an opening 45 through which theneck 39 of the screw passes are secured to the clamping head 42 andprevent the withdrawal of the enlargement 40 of the screw from therecess 41 in the head. As shown in Figure 10, the distance between thebottom of the recess 41 in the head 42 and the flange 44 is somewhatgreater than the depth of the enlargement 40 on the screw so as toprovide suflicient clearance to permit limited vertical movement of thehead 42 relative to the screw, the arrangement, in effect, constitutinga lost motion connectionbetween the head and the screw. The projectingends 4601 pins secured to the enlargement 40 on the end of the screw aredisposed in slots 47 formed in opposite sides of the recess 41 in thehead 42 in order to hold the head against rotary movement relative tothe screw. The head 42 is provided with a pair of spaced downwardlyextending legs 48 adapted to engage the opposite sides of the top faceof a mold positioned under the screw when the latter is moveddownwardly. Normally, the head 42 will be in a position out of contactwith the mold underneath. In this position of the screw and head, theywill be in the relative positions to each other shown in Figure 10, fromwhich it will be noted that,

the head 42 being suspended from the lower end of the screw 34, theflange 44 on the head will be in engagement with the enlargement 40, andthere will be considerable clearance between the bottom end of the screwand the bottom of the recess 41 in the head. When it is desired to movethe'head into engagement with the mold so as to hold the latter instripping position, the motor 32 is run in a direction to drive thescrew 34 downwardly. When the legs. 48 of the head 42 engage the topface of the mold, the head will become supported by the mold, andfurther downward movement of the head will be prevented. move downwardlyuntil the extreme bottom end thereof engages the bottom of the recess41in the head, whereupon the motor 32 will be stopped automatically in amanner later to be described.

The mechanism for controlling the operation of the motor consists'partlyin means carried by the screw 34 and responsive to engagement of thehead 42 with a mold for breaking a circuit However, the screw willcontinue to through the motor. The screw 34 is formed with a ecntralbore 49 in which a rod 50 is mounted for sliding movements, the lowerend of the rod resting against the bottom of the depression 41 in thehead 42 and the upper end of the rod extending through a guide 51secured to the top end of the screw. An angle member 52 is secured tothe top end of the rod 50 and is adapted, when the latter is raisedrelative to the screw, to engage and operate simultaneously three limitswitches I, II, and III carried by a bracket 53 fixed to the upper endof the screw 34. When the screw and head are in the relative positionsshown in Figure 10, the rod 50 will occupy a lower position with itsbottom end in contact with the head 42 and with the angle member 52disposed below the operating arms of the limit switches I, II, and III.When the screw is moved downwardly and the head into engagement with themold so as to produce movement of the screw downwardly relative to thescrew in the manner heretofore described, the rod 50 will be movedupwardly relative to the screw and to the switches I, II, and III,resulting in engagement of the angle member 52 with the switches andoperation of the latter. As will be described later, operation of theswitch I automatically will stop the motor 32, whereupon the screw andhead will be maintained in the positions shown in Figures 1 and 2 untilthe motor has been reversed and the screw and head retracted. The otherlimit switches II and III are operated simultaneously with the limitswitch I by the angle member 52, operation of the switches effectingautomatic control of the means for positioning the molds under the screwand the means for operating the stripper rod respectively in a mannerfully to be described later.

In order to provide for automatically stopping the motor 32 when thehead 42 has been raised clear of a mold underneath, I provide a limitswitch IV mounted on a vertical member 22 of the tower and disposed inthe path of an arm 55 carried by the head 42. In operation, when thescrew and head are moving upwardly, the arm 55 will engage the operatingarm of the switch IV and will open the latter so as to stop the motorand bring the screw and head to rest. The switch IV is positioned atsuch a height that it will be operated to stop the motor when the screwhas been raised to a position providing a safe clearance between thebottom of the head and the top of the molds. In some cases it isnecessary that the locomotive which brings the cars from the pouringstation to the stripping apparatus pass under the tower 21. In suchcases it may be necessary to raise the screw and head to a positionconsiderably higher than that in which they are stopped by the operationof the switch IV. Accordingly, I provide means to be described later foreffecting continued operation of the motor after the switch IV has beenoperated. In order to prevent overtravel of the screw and head duringtheir upward movement, I provide another switch V mounted on a crossmember 23 of the tower and having its operating arm disposed in the pathof the arm 55 on the head. When the screw and head have been movedupwardly to an extent providing the clearance which may be necessary forthe passage of the locomotive, the arm 55 will engage the operating armof the switch V and will actuate the latter in a manner to stop themotor 32, thereby preventing overtravel of the screw and head andinsuring against damage to the parts. In order to prevent overtravel ofthe screw downwardly, for example, when no mold is positioned under thescrew and the latter is moved downwardly through inadvertence, I providea limit switch VI mounted on the frame 24 and having its operating armdisposed in the path of the bracket 53 on the screw. When the screwmoves downwardly toward the limit of its travel, the bracket 53 willengage the operating arm of the switch and actuate the latter to stopthe motor, the breaking of the circuit through the motor beingaccomplished under the control of the switch VI by means to be describedlater.

Referring now to the mechanism B for operating the stripper rods 13-13,two hydraulic cylinders 56-56 are mounted directly under the screws3434' respectively, being carried by brackets 57-57 depending from afloor plate 58. The mechanism associated with the cylinder 56 only willbe described; it being understood that that associated with the cylinder56 is similar and that the parts thereof are designated by correspondingreference numerals, which, how-.

ever, are primed. A stripper plunger '59 is mounted in the cylinder 56and is provided with a reduced stem 60 mounted for sliding movements ina guide bearingsleeve 61 carried in a projection 62 formed on the floorplate 58. An apron 63 is secured to the stem 60 of the plunger, and anangle section 64 is connected to the apron and extends outwardlytherefrom for cooperation with the operating arms of switches VII, VII'and VIII mounted on the tower struc ture base as shown in Figures 2, 9and 20. The operating arm of the switch VIII is urged upwardly but isadapted to be held in its Figure 2 position by the extension 64 when theplunger 59 is in its lower position, this switch serving to controloperation of the means for positioning molds under the plungers, as willbe described more fully later. The operating arms of the switches VIIand VII are adapted to be engaged by the projection 64 when the plunger59 is raised in order respectively to effect control of the operation ofthe plunger so as to bring the latter to rest after the strippingoperation has been performed and automatically to efiect operation ofthe screw motor 32 in the reverse direction to start the screw movingupwardly.

In accordance with one feature of the invention, I provide means forsupplying fluid under relatively low pressure and at a high rate to thecylinder 56 for raising the plunger 59 into engagement with the stripperrod 13 and for raising the latter to strip the mold when there is nounusual sticking of the ingot in the mold, and means for supplying fluidunder relatively high pressure and at a relatively low rate for raisingthe plunger 59 upwardly when the ingot sticks in the mold to such anextent as to offer suflicient resistance to the operation of the plungerto resist the pressure supplied by the low pressure, high rate supplymeans. In the form shown, I provide a pump 65 adapted to deliver fluidunder relatively low pressure but at a relatively high rate, a pump 66adapted to deliver fluid urider relatively high pressure but at arelatively low rate, a motor 67 connected to both of the pumps fordriving the latter, and hydraulic connections between the pumps and thecylinders 56 and 56. The motor 67 is arranged to drive the pumpscontinuously, the supply of fluid under pressure to the cylinders beingcontrolled by means of valves interposed in the connected piping.- Bothpumps are preferably of the well known radial variable discharge type,for example, such as is shown in Patent No. 1,077,979, granted to Hele-Shaw et a1. November 11, 1913. The construction and operation of pumpsof this-kind are well known, and no detailed description thereof isconsidered necessary. The pumps and 66 are provided respectively withcontrol mechanism 68 and 69 for limiting the maximum discharge pressureof each, the control mechanism-also being of well known construction, sothat no disclosure of the details thereof is necessary. Generallystated, the arrangement is such that when the discharge pressure reachesa predetermined value the control mechanism will operate to decrease therate of discharge of the pump to maintain the discharge pressure at apredetermined maximum value. The control mechanism 68 of the pump 65 isarranged to limit the discharge pressure of the latter to a thousandpounds per square inch, and the control mechanism 69 0f the pump 66 isarranged to limit the maximum discharge pressure thereof to threethousand pounds per square inch.

A pipe line '70 leads from the pump 65 to the cylinder 56, and a branchpipe '71 leads from the pump 66 to the' pipe line 70. Suction pipes '72and '73 are connected between the pumps 65' and 66 respectively and atank or reservoir T. A three way valve 74 of conventional design isinterposed in the pipe line '70, and a branch pipe line 70' leads fromthe valve -74 to the cylinder 56.

The valve 74 is provided with a stem 75 (see Figure 11) the position ofwhich controls the passage of fluid through the pipelines '70 and 70'.When the stem is in its lower position relative to the valve casing,fluid will flow through the pipe line '70, to the cylinder 56, but whenthe stem is moved to its upper position the valve will divert fluid fromthe pipe line 70 and direct it through the pipe line 70 to the cylinder56. Thus, by changing the position of the stem 75, the fluid supplied bythe pumps 65 and 66 may be directed either to the cylinder 56 or to thecylinder 56 in order to operate either the plunger 59 or the plunger59', whichever may be desired. A cross bar 76 is secured to the casingof the valve 74, and two spaced guide rods 77 are secured to the crossbars and are connected at their lower ends by means of a bar 78. A crosshead 79 is secured to the stem '75 and is mounted for sliding movementson the guide rods 77. Springs 80 interposed between the cross bar 76 andthe cross head 79 urge the latter constantly to its lower position.wherein fluid will be directed through the pipe 70 to the cylinder 56.-Thrust rods 81 connected to the cross head extend downwardly forconnection with a motor actuated mechanism 82. Operation of themechanism 82 under the control of means later to be described willeffect an upward movement of the thrust rods 81, and consequent movementof the valve stem '75 to its upper position wherein fluid will bediverted from the cylinder 56 and will be delivered to the cylinder 56.As is apparent from the foregoing description, the three way valve 74functions to cause fluid discharged by the pumps 65 and 66 to bedirected either to the cylinder 56 or the cylinder 56', as is desired.

When it is desired to maintain the plungers 59 and 59' in theirretracted positions, and also when it is desired that the plungers beallowed to return to their retracted positions after completion of thestripping operation, it is necessary to divert the flow of fluid fromboth cylinders. For cfiecting the diverting of fluid or the exhaustingof fluid from the cylinder 56, I provide a fluid exhaust pipe 83connected at one of its ends to the pipe 70 between the valve 74 and thecylinder 56 and connected at its other end with the tank T, and a twoway valve 84 of conventional design interposed in the exhaust pipe 88.The valve 84 provided with a stem 85 which is movable vertically to anupper positiorf to prevent the flow of fluid through the exhaust pipe 83and to a lower position to permit the free flow of fluid through thepipe 83. it being noted that when'the stem is in the upper position,preventing flow of fluid through the pipe 83, fluid discharged throughthe pipe 70 cannot return to the tank and will be directed to thecylinder 56. A cross bar 86 is secured to the casing of the valve 84,and guide rods 87 carried by the cross bar extend downwardly therefromand are connected at their lower ends by a bar 88. A cross head 89 isconnected to the valve stem 85 and is mounted for sliding movements onthe rods 87. Springs 90 interposed between the cross bar 86 and thecross head 89 urge the cross head and the valve stem 85 constantly totheir lower positions, wherein fluid is permitted to pass through theexhaust pipe 83. Thrust rods, 91 connected to the cross head 89 extenddownwardly. for connection with a motor operated mechanism 92 which isoperated under the control of means to be described later for raisingthe thrust rods 91 and the stem 85 so as to cut off flow through thevalve 84 and consequently through the pipe 83.

A two way valve 84 similar to the valve 84 and provided with controlmechanism similar to that described in connection with the valve 84 isinterposed in an exhaust pipe 83 one end of which is connected to thepiping '70 and the other end of which is connected to the tank T. Whenthe stem 85' of the valve 84' is in its lower position, the pipe '70will be afforded free communication with the tank T, whereas, when themechanism 92' is operated to raise the stem 85', flow of fluid throughthe pipe 83' will be prevented.

In operation, assuming that the parts are in the position shown inFigure 2, the stem 75 of the valve 74 will be held in its lower positionunder the urge of the springs 80, so that the discharge from the pumpswill be directed towards the cylinder 56, and the stem 85 of the valve84 will be held in its lower position under the urge of the springs 90so as to permit the free flow of fluid through the exhaust pipe 83.Fluid discharged through the pipe 70 thereby will be by-passed throughthe pipe 83 to the tank T, so that no pressure will be exerted upon theplunger 59. When it is desired to raise the plunger 59 into engagementwith the stripper rod 18 so as to effect stripping of the ingot, themotor mechanism 92 associated with the valve 84 is operated to move thestem 85 to its upper position so as to cut off flow through the pipe 83.Thereafter fluid discharged through the pipe '70 will be directed to thecylinder 56 and will act upon the plunger 59 to raise the latter tostrip the ingot. It will be understood that both pumps 65 and 66 supplyfluid under pressure to the pipe 70 and to the cylinder 56 to effectoperation of the plunger 59. Should the ingot stick to the mold so as topresent an abnormal resistance to the movement of ihe lunger 59,pressure will build up in the cylinder 56 to a valve beyond the maximumdis- 15 charge pressure of the pump 65 but less than the maximumdischarge pressure of the pump 66. When this occurs, a check valve 93interposed in the pipe 70 between the pump 65 and the pump 66 andarranged to permit flow of fluid in the direction of the arrow X inFigure 2 but not in the opposite direction will be closed by the excesspressure on the left hand side of the valve. This will prevent the fluiddischarged from the pump 66 from being forced back through the pump 65,so that the total discharge of the high pressure pump 66 will bedelivered to the cylinder 56 so as to overcome the pressure ofiered bythe sticking of the ingot. While the check valve 93 is held closed soasto prevent back discharge of fluid into the pump 65, the controlmechanism-68 will operate in a well known manner to prevent furtherdischarge of the pump. When the plunger 59 has been raised to the extentnecessary to strip the ingot and to bring the uppermost notch 16 of thestripper rod opposite the end of the latch rod 17, the projection 64 onthe apron 63 willoperate the switch VII so as to break a circuit throughthe motor operated mechanism 92 and to permit the springs 90 to returnthe stem of the valve 84 to its lower position wherein flow of fluid ispermitted through the valve and through the exhaust pipe 83. FluidcOIlLZllfii-Bd m the cylinder 56 will then be expelled through the pipe'70 and the exhaust pipe 83 to the tank; '1', and the plunger 59 willdescend to its retracted position. In order to effect operation of theplunger 59', the motor operated mechanism 82 is energized to move thevalve stem 75 to its upper position so as to direct the discharge fromthe pumps through the pipe '70 to the cylinder 56'. The valve 84 willthen be closed in the manner already described to prevent fiow of fluidthrough the exhaust pipe 83, and fluid will be directed through the pipe70 to the cylinder 56-to move the plunger 59' upwardly. The valve 84will then be opened to permit fluid contained in the cylinder 56' toreturn through the pipe 70 and the exhaust pipe 83 to the tank T so asto permit the plunger 59 to descend to its lower position.

Referring now to the mold positioning means C best shown in Figures 1,3, 4, 5, and 6, a racki bar 94 disposed longitudinally of the tracks Fand midway between the latter is provided at its opposite ends withtransverse shafts 95 upon the projecting ends of which are journalledwheels 96 having rolling engagement with the bottom flanges 01longitudinally disposed I beams 97. The right hand end of the rack bar,as viewed in Figures 1 and 4, is bifurcated to provide a pair of spacedarms 98. A pin 99 fixed in these arms and extending across theintervening space serves to mount pivotally a pawl 100, the nose 101 ofwhich is adapted, when the pawl is rocked in a counter clockwisedirection as viewed in Figure 1, to be received in an opening 102 formedin a downwardly extending part 103 of one of the cars E or between twoadjacent cars. The pawl 100 extends up through a slot in the floor plate58 (see Figure 2) and is movable longitudinally of the tracks F with therack 94. Both ends of each car E are provided with downwardly extendingsections 103 formed with openings 102, each of which openings is adaptedto receive the nose 101 of the pawl when the latter is moved upwardlyfrom below an opening 102.

The pawl is formed with a weight arm 105 disposed on the opposite sideof the pin 99 from the nose 101, this weight serving constantly to urgethe nose of the pawl upwardly into operative position. In order toprovide for the actuation of the pawl to disengage the nose 101 thereoffrom a car, I provide means engageable with the pawl irrespective of theposition of the rack bar for rotating the pawl in a clockwise directionto move the nose 101 downwardly. In the embodiment shown in thedrawings, this means includes a pair of spaced levers 10610'7 locatedunder the rack bar, these levers being similar and of equal length. Thelever 106 is carried by a pin 108 supported in a fixed bracket 109, andthe lever 107 is secured to a rock shaft 110 journalled in a fixedbracket 111. A rail 112 (see Figure 1) is pivoted at its opposite endsto the levers 106 and 107, the levers and the rail 112 constituting aparallelogram linkage. A hand lever 113 (see Figure 3) is fixed to theshaft 110 and is operable to rock the latter and the levers to the leftto move the rail 112 downwardly or to rock the levers to the right tomove the rail upwardly with respect to the rack, maintaining the railparallel to the rack at all times. When the rail is moved upwardly, itwill engage a roller 114 carried by a pin 115 supported at the lowerside of the weight arm 105 of the pawl. In operation, assuming the partsto be in the Figure 1 position, in order to effect disengagement of thenose 101 of the pawl from the car, the hand lever 113 will be operatedto rock'the levers 106 and 10'? toward the right as viewed in Figure 1.This will raise the rail 112 into engagement. with the roller 114 so asto rock the pawl in a clockwise direction, thereby moving the nosedownwardly and out of engagement with the car. The rack then may bemoved to the left without the cars being moved, and the rail 112 loweredso as to permit the nose 101 of the pawl again to move upwardly and toengage an opening 102 in a car near the left hand end of the travel ofthe rack. It will be observed that the rail 112 isengagcable with thepawl roller 114 irrespective of the position of the rack longitudinallyof the tracks F.

It is desirable to provide means engageable with the pawl 100 when thelatter is in operative position as shown in Figure 1 for preventingaccidental disengagement of the pawl. To this end a latch 116 is mountedon a pin 11'? carried by the arms 98 at the right hand end of the rack.The nose 118 of the latch is engageable with the top face of aprojection 119 on the weight arm 105 of the pawl when the latter is inoperative position. With the latch in the position shown in Figure 1, itwill not be possible for the pawl to become disengaged from the car. Thebottom arm 120 of the latch is disposed at an angle to the arm carryingthe latch nose, and the weight of the arm 120 urges the latch in aclockwise direction so as to drop into engagement with the projection119 of the pawl when the curved lower face of the projection 119 passesthe curved upper face of the nose 118 on the latch. Thus, assuming thepawl to be in its inoperative position with the projection 119 locatedabove the latch nose 118, and assuming the rail 112 to be lowered so asto permit the weight arm 105 of the pawl to be lowered, the projection119 momentarily will move the latch nose to the left, after which thelatter will drop into the position shown in Figure 1 and will maintainthe pawl against accidental displacement. A roller 121 mounted on a pin122 carried by the lower arm of the latch is en gageable by the rail 112when the latter is raised so as to cause the latch to be rocked in acounter clockwise direction to swing the nose 118 thereof clear of theprojection 119, permitting the pawl to move to its inoperative position.

Means for operating the rack in both directions are illustrated inFigures 5 and 6. A motor 123' is geared through a speed reducing geartrain 124 to a shaft 125 supported in fixed bearings 126. A pinion 127fixed to the shaft is in mesh with the rack 94. The motor is providedwith a conventional automatic brake 128 which functions to stop themotor quickly when a mold has been spotted in stripping position. Theoperation of the motor for driving the rack is controlled in part bymanually operated means and in part by means automatically responsive tothe movement of certain parts of the apparatus, as will be set forthmore fully.

Referring to Figures 2 and 7, each car E is provided with a plurality ofspaced projections 131 each of which is aligned with a pair of openings11 in the associated car, and hence with the associated stripper rod 13.Vertically spaced switches IX and X are mounted on a vertical member 22of the tower structure substantially in a vertical plane containing thescrews and stripper plungers. The switch X is not shown in Figure 7because it is located directly under the switch IX. A bracket 132likewise carried by the vertical members 22 of the tower serves to mountpivotally a pin 133 disposed in the plane containing the screws andstripper plungers, and a lever 134 is carried by the pin 133. One arm135 of the lever is disposed for engagement by an advancing projection131 on a car, and the other arm 136 of the lever is adapted to engagethe operating arms of the switches IX and X when the lever 134 is rockedby the advancing projection 131. A spring 137 connected between the arm135 of the lever and a fixed bracket 138 normally maintains the leverout of engagement with the operating arms of the switches.

In operation, assuming that the rack motor is started so as to advancethe rack and the mold cars to position the next mold under the screws,the rack and cars will move to the right as viewed in Figure 1 until theprojection 131 opposite the mold moving into position engages the lever134 so as to rock the latter and operate the arms of the switches IX andX. As will be described later, the operation of the switch IX at thistime will stop the rack motor automatically, thereby bringing the carsto rest with the ingot mold positioned directly under the screw. and theoperation of the switch X will prepare the screw motor circuit for beingclosed by the manual operation of another switch. Limit switches XI andXII mounted at opposite ends of the rack supporting rails 97 are adaptedto be operated by the rack at limits of its forward and reverse travelrespectively for preventing overtravel of the rack.

Figures 12 to 15, inclusive. show a modified form of mold engaging headadapted to be carried by the lower ends of the screws 34, the headsembodying the invention in this form being adjustable to adapt thedownwardly extending legs for engagement with opposite sides of the topfaces of molds of difierent sizes. The modified form of head generallydesignated 139 comprises a body part 140 formed along its outer edgeswith spaced depending flanges 141 formed along their inner faces withslots or grooves 142. A pad 143 is disposed between the flanges 141 atthe center of the body 140. Two mold engaging legs 144 are mounted attheir top ends between the flanges 141 of the body for sliding movementsrelative to the body, the legs being provided on their opposite sideswith tongues 145 which fit in the grooves 142 of the body flanges. Theupper ends of the legs 144 are formed with reversely threaded openings146 which respectively receive the reversely threaded ends of a captivescrew 147. Collars 148 fixed to the screw at the inner ends of thethreaded portions thereof engage the pad 143 for holding the screwagainst longitudinal movement. Hand wheels 149 fixed to the oppositeends of the screw 147 provide for the rotation of the latter to causethe legs 144 to move inwardly or outwardly in order to adapt the headfor cooperation with molds of relatively small or relatively greatwidth.

The control circuit for the rack operating motor 123 is showndiagrammatically in Figure 16. The motor is arranged to be supplied withpower from a supply main comprising conductors 150 and 151. The shuntfield of the motor is connected directly across the main by means of aconductor 152, a cut-out switch 153 being interposed in the conductor topermit the motor circuits being totally disconnected from the line whendesired. The opposite sides of the motor armature are connected to midpoints of conducin the conductor 154 on opposite sides of its point ofconnection to the armature, and contactor switches 160 and 161 areinterposed in the conductor 155 on opposite sides of its connection tothe armature. The switches 159 and 161 are of the well known doublecontact type, and are so arranged that when in their lower positions, asshown in Figure 16, they will close a circuit through a brake resistance162, connecting the latter directly across the armature to effectregenerative braking of the rack motor.

The arrangement is such that, when the coils of the contactor switches159 and 160 are energized, these switches, being closed, will complete acircuit through the motor armature in such a direction as to cause themotor to operate the rack in a forward direction, whereas, when thecoils of the switches 158 and 161 are energized to close these switches,the circuit will be closed through the armature in the oppositedirection to reverse the motor and to operate the rack in the reversedirection.

The contactor switches previously referred to are arranged to beoperated automatically in accordance with the movements of the moldears, the hold-down screw, and the stripper plunger. A conductor 163leads from the side 151 of the main through the normally closed limitswitch II carried by the hold-down screw 34, the normally closed limitswitch II" carried by the screw 34, the limit switch VIII normally heldclosed by the plunger 59, and the' limit switch VIII normally heldclosed by the plunger 59'. A conductor 164 leads'from the conductor 163through a IX is shunted by a manually operable push button 166.

A conductor 167 leads from the conductor 163 through a reverse masterswitch 168, the normally closed rack operated limit switch XII, the coilof the contactor switch 158, the coil of the contactor switch 161, andthence to the side 150 of the main.

In operation, assuming that the leading mold car has not been moved intoposition under the lower, the switches all will be in the positionsshown in Figure 16 and the rack motor will be at rest. When it isdesired to move the cars forwardly to position the first mold on theleading car directly under the hold-down screw, the master switch 165 isclosed manually. This will complete a circuit through the conductor 163,the switches II, II, VIII, VIII, 165, IX, and XI, the conductor 164, thecontactor coil 160, and the contactor coil 159, closing the contactors160 and 159 and causing the motor to drive the rack forwardly. When thefirst mold on the leading car arrives directly under the screw 34, theprojection 131 opposite this mold will engage the operating arm 135 andwill rock the lever 134 to open the limit switch IX, thus breaking the'circuit through the coils of the switches 159 and 160 and permittingthese contactors to drop out, thereby stopping the rack motor. Wheneither the head 34 or 34' has been moved into engagement with the mold,the rod 50, or 50' as the case may be will be operated to open theswitch II or II in the manner previously described, thus preventinginadvertent operation of the rack motor when the mold is held by thehead. Similarly if either the plunger 59 or the plunger 59' is above itslower position, one or the other of the switches VIII or VIII will beopened and inadvertent operation of the rack motor during a strippingoperation will be prevented.

When the ingot has been stripped from the first mold and it is desiredto position the next mold under the screw 134, the push button 166 isclosed momentarily to shunt the then open switch IX. The circuit willthereby be closed through the coils of the contactors 160 and 159,causing the motor to drive the rack and cars forwardly. After theprojection 131 has cleared the operating arm 135, the latter will bereturned to its normal position by the spring 137, permitting the limitswitch IX to close. The push button 166 is then opened, and the circuitthrough the contactor coils 160 and 159 will be closed through theswitch IX. When the next projection 131 engages the operating arm 135,the switch IX again will be opened to bring the next mold to rest in aposition directly under the screw 134. In this manner the molds on theseveral cars may be advanced successively to stripping position simplyby closing the push button 166 momentarily after each mold is stripped.Should the rack reach the limit of its forward travel, it will open thelimit switch XI so as to prevent a circuit being closed through thecoils of the contactor switches 159 and 160 When it is desired to returnthe rack to its rearmost position, the master switch 165 is opened, andthe master switch 168 is closed.

This will complete a circuit through the conductors 163 and 167, themaster switch 168,

the rack operated limit switch XII, the coil of the contactor switch158, and the coil of the contactor switch 161, whereby the switches 158and 161 will be closed and the motor will operate in the reversedirection to return the rack to its rearmost position. In order to stopthe motor when the rack has reached the desired position, the masterswitch 168 is opened. If the operator fails to open the master switch168 before the rack reaches the limit of its rearward travel, the rackwill engage and operate the limit switch XII to open position so as tobreak the circuit through the coils of the contactor switches 158 and161 so as to bring the rack to rest automatically.

Figure 17 shows the electrical control circuit for the screw operatingmotor 32. The shunt field is connected directly across the line 150- 151by means of a conductor 169, a cut-out switch 170 being interposed inthis conductor to enable the motor to be disconnected from the line whenthe apparatus is not in use.

Opposite sides of the armature of the motor 32 are connected to the midpoints of conductors 170 and 171. The opposite ends of these latterconductors are connected by conductors 172 and 173, the conductor 172being connected to the side 151 of the supply line and the conductor 173being connected to the side 150 of the line. The series field of themotor and a contactor switch 174 are interposed in series between theconductor 173 and the side 150 of the supply line. Contactor switches175 and 176 are interposed in the conductor 170 on opposite sides of itsconnection to the motor armature, and contactor switches 177 and 178 areinterposed in the conductor 171 on opposite sides'of its connection tothe armature. The contactor switches 176 and 178 are of the type wellknownas double contact switches and are adapted when both are in theirFigure 17 positions to connect a brake resistance 179 directly acrossthe motor armature so as to effect regenerative braking of the motor 32.

The arrangement of the contactor switches referred to is such that, whenthe switches 175 and 178 are closed, the motor 32 will run in adirection to move the screw 34 downwardly, and,

when the switches 176 and 177 are closed, the

motor 32 will run in the reverse direction to move the screw upwardly.The contactor switch 174 is normally open and is closed only wheneither.

pair 175-178 or 176177 of contactor switches is closed, the purpose ofthe switch 174 being to break the circuit through the shunt brake whenthe motor is not running. 1

The opening and closing of the contactor switches for effectingoperation of the motor in either direction is controlled automaticallythrough the operation of limit switches previously referred to. In thecontrol circuit shown, a conductor 179' leads from the conductor 172through the car operated switch X and through a contactor switch 180which is normally closed and which is opened when fluid is beingdelivered to the cylinder 56, the operation of the switch 180 beingdescribed more in detail hereinafter. A push button 181 is connectedacross the car operated switch X for closing the circuit when the switchX is held open.

A conductor 182 leads from the conductor 179' through a manuallyoperable master switch 133, the limit switch I carried by the hold-downscrew, the limit switch VI mounted on the tower, the coil of thecontactor switch 175, the coil of the contactor switch 178, the coil ofthe contactor switch 174, and thence to the side 150 of the main line.In operation, assuming that no mold has been positioned under the screw134, the master switch 183 will be closed to place the apparatus inreadiness for operation. When the first mold is moved into strippingposition, the projection 131v opposite such mold will engage switch 183,the limit switches I and VI, the coil of the contactor switch 175, thecoil of the contactor switch 178, and the coil of the contactor switch174. The contactor switches 175, 178, and 174 thereby will be closed,and the'motor will drive the screw downwardly toward the mold. When thehead 43 engages the mold in a manner to operate the rod 50, thelatterwill move the switch I to open position, thus breaking a circuit throughthe coils of the contact switches 175, 178, and 174 so as to stop themotor. If, through inadvertence, the motor 32 should be caused to drivethe screw downwardly when no mold is in stripping position, the limitswitch VI will be opened upon engagement of the bracket 53 with theswitch arm so as to break the circuit and prevent over travel of thescrew.

That part of the circuit which controls the operation of the motor formoving the screw upwardly will now be described. A conductor 184 leadsfrom the conductor 179 through a master switch 185, the limit switch Vcarried by the tower, the coils of the contactor switches 176, 177, and174, and thence to the side 150 of the supply line. In operation, if itis desired to move the screw upwardly under manual control, the masterswitch 185 is closed so as to effect closing of the contactor switches176, 177, and 174, whereby the motor will operate in the reversedirection to move the screw upwardly.

In accordance with the invention, means are provided for starting thescrew on its upward travel as soon as the stripping operation has beencompleted. In the circuit shown, a contactor switch 186 is connecteddirectly across the manually operable switch 185, and means are providedfor closing the contactor switch automatically upon the completion ofthe stripping operation. To this end a conductor 187 leads from theconductor 172 through the coil of the contactor switch 186, the coil ofa contactor switch 188, the plunger operated limit switch V111: and thelimit switch IV to the side 150 of the line. A conductor 189 isinterposed between one side of the contactor switch 188 and the limitswitch IV, so that, when the contactor switch 188 is once closed throughthe closing of the switch VIIa, the circuit will be made across thepoints of the contactor 188, maintaining the coil of the latterenergized so as to seal the circuit closed even after the switch VIIa isopened.

In operation, assuming that the screw is in its lower position with thehead 43 in engagement with the mold, the switches 186, 188, VIIa, and IVwill be in the positions shown in Figure 17, and the circuit through thecoils of the contactor switches 176, 177, and 174 will be open. When theplunger 59 reaches the uppervlimit of its travel, it will engage andclose automatically the switch VIIa. This will close a circuit throughthe conductors 172 and 187, the contactor switch 186, the closed switchWM, and the switch VII. Energizing of the coil of the contactor switch186 will close this switch so as to complete a circuit around the masterswitch' 185 so that the coils of the contactor switches- 176, 177, and174 will be closed in the manner previously described, thereby startingthe motor in the reverse direction so as to move the screw upwardly. Itwill be understood that the switch VIIa will be held closed for a shorttime only, that is, only during the time when the plunger- 59 is in itsextreme upper position. However, as previously stated, once the coil ofthe contactor switch 188 has been energized, this contactor in closingseals its own circuit, so that, even after the switch VIIa is opened andthe plunger moved downwardly, the motor will continue to drive the screwupwardly. When the screw reaches the desired upper limit of its travel,the limit switch IV will be operated in the manner previously describedso as to break the circuit through the coils of the contactors 176, 177,and 174 and to bring the screw to rest. If it is desired to move thescrew still further upwardly in order to permit the passage of alocomotive under the tower, the switch 185 may be closed. As previouslystated, this will close the contactors 176, 177, and 174 so as tooperate the motor in the reverse direction to move the screw upwardly.When the screw approaches the extreme limit of its upward travel, theswitch V will be operated as previously described so as to break thecircuit through the coils of the contactors referred to, causing thecontactors to open and stopping the motor.

The control circuit for the motor mechanism 92 which operates the valve84 is shown in Figure 18. A conductor 190 connects one side of the motor92 to the side 150 of the main line, and a conductor 191 connects theother side of the motor to the side 150 of the main line. Normally open,contactor switches 192, 193 are interposed respectively in theconductors 190 and 191.

A conductor 194 leads through the coils of the contactors 192 and 193and through the coil of the contactor 180 of the screw motor controlcircuit shown in Figure 17, and then through the plunger operated limitswitch VII and the limit switch I11, carried by the top of the screw 34to the conductor 191, being connected to the latter between thecontactor 193 and the motor 92.

A conductor 195 is connected across the contactor 193, and a manuallyoperable push button 196 is interposed in the conductor 195.

In operation, assuming that the head 43 has not yet moved intoengagement with the mold, the various switches will be in the positionsshown in Figure 18. When the head engages the mold so as to move the rod50 upwardly, the switch III 125 will be closed in the manner describedpreviously. This will set up the valve control circuit, placing it inreadiness for eifecting the start of operation of the motor 92 undermanual control of the push button 196. At this time, before the push 130button is closed, there will be no circuit closed through the coils ofthe contactor switches 192 and 193,'and consequently these switches willremain open. When the operator closes the push button 196, a circuitwill be closed through the 1 conductor 194, the coils of the contactors192 and 193, the coil of the contactor (Figure 17) the limit switch VII,the limit switch m, the push button 196 and the conductors and 191. Thiswill energize the coils of the contactors 192 and 140 193 so as to closethese switches to start the motor 92. After the motor has been started,the push button is opened, but due to the prior closing of plunger 59will be moved upwardly to perform a stripping operation. When thestripping operation has been completed, the projection 64, carried bythe plunger 59, will open the limit switch VII, as previously described,thereby breaking the circuit through the conductor 194 and consequentlydeenergizing the coils of the contactors 192 and 193 so as to permit thelatter to open, whereby the motor 92 will be stopped and the springs 90will return the valve stem to its lower position so that the cylinder 56will be connected to the tank T and the plunger 59 will return to itslower position.

It will be noted that when the coils of the contactors 192 and 193 areenergized so as to effect operation of the motor 92 and upward movementof the plunger 56, the coil of the contactor 180 likewise will beenergized, so that the switch 180 will be opened, and it will beimpossible to start operation of the screw motor 32 while the plunger ismoving upwardly.

When the limit switch VII is opened and the plunger begins to movedownwardly, the coil of the contactors 180 will be deenergized, therebyallowing the contactors 180 to close and set up the control circuit forthe screw motor 32. Simultaneously with the opening of the switch VII,the switch VIIa will be closed so as to start the screw motor 32 in adirection to move the screw 34 upwardly in the, manner stated indescribing the circuit shown in Figure 17.

Figure 19 shows the control circuit for the' motor mechanism 82 whichoperates the valve '74 to shift the flow of fluid from the cylinder 56to the cylinder 56. A conductor 19'? is interposed between one side ofthe motor 82 and the side 150 of the main line, and a conductor 198 isinterposed between one side of the motor 82 and the side 151 of the mainline. 199 is interposed in the conductor 198. When the switch 199 isopened so that the motor 82 is not operating, the springs 80 of thevalve mechanism 74 will-maintain the valve stem in its lower position sothat fluid will be directed to the cylinder 56. When the switch 199 isclosed so as to start the motor 82, the valve stem 75 will be moved toits upper position and fluid will be directed to the cylinder 56'.

It will be understood that circuits similar to those shown in Figures 17and 18 are provided for controlling the operation of the screw 34' andthe valve 84'. The circuit shown in. Figure 16 for controlling the rackmotor is the only circuit needed for this purpose, inasmuch as the moldson one side of the car are located directly opposite the molds on theother side of the car so that the molds are spotted under the tower inpairs.

The various elements of the electrical control circuits have been showndiagrammatically only, it being understood that the switches,contactors, push buttons and the like are all of standard constructionand that, the details thereof are not relevant to the invention. Theusual safety devices such as overload and low voltage circuit breakersmay be included in the circuits but have been omitted from thedisclosure in the interest of simplicity since they are not essential toan operative arrangement.

It is apparent that apparatus constructed and arranged in accordancewith my invention facilitate the stripping of ingots from big end upmolds to such an extent as to render the production of high qualitysteel more economical than has been possible with stripping apparatusem- A manually operable switch.

ployed heretofore. locked control of the mold positioning, holding, andstripping mechanisms provide for increased stripping speedand greaterproduction from a given number of molds, but the control also preventsthe accidental operation of any one of the mechanisms at such time asmight result in injury to the machinery or operators.

From the foregoing it will be apparent that in accordance with themethod of controlling the operation of the stripping apparatus I utilizereturn movement of the stripping device for effecting movement of theholding device to inoperative position, and utilize stripping movementof the stripping device for preventing movement of the mold supportduring the stripping operation and for preventing movement of theholding device during the .stripping operation. Movement of the moldsupport is utilized for arresting movement thereof when a mold hasreached stripping position as well as for controlling the operation ofthe stripping device. Movement of the holding device in turn is utilizedfor controlling operation of the stripping device and the mold support.In accordance with a further feature of the invention, the method ofstripping ingots consists in holding the mold stationary,

applying stripping pressure to the ingot, and,

in case the ingot has a tendency to stick in the mold, automaticallyapplying increased pressure to the ingot to assure stripping thereof.

Although the apparatus disclosed herein embodies the invention in apractical and in the at present preferred form, it will be understoodthat various modifications may be made without departing from the spiritof the invention as defined in the claims.

I claim: 1. The combination with an ingot stripping apparatus; of a moldsupport mounted for movements with respect to the apparatus forpositioning a mold in stripping position relative to said apparatus andmechanism for moving said support comprising a member mounted formovements in the direction of travel of the mold support, means fixedwith respect to said stripping apparatus and having driving connectionwith said member for operating the latter, coupling means connected toand being movable with said member and also being movable relative tosaid member into and out of engagement with said support'for effectingdriving relation between said Not only does the inter-' member and saidsupport, and a control device operatively connected to said couplingmeans and being operable to move said coupling means. into or out ofengagement with said mold support.

2. The combination with an ingot stripping apparatus; of a mold supportmounted for movements with respect to said apparatus for positioning amold in stripping position relative to said apparatus and mechanism formoving said support comprising; a bar mounted for reciprocatory movementof limited extent in the direction of travel of said support, a motorfixed with respect to said stripping apparatus and being operativelyconnected to said bar for reciprocating the latter, and a. drivingconnection mounted on said bar for movements therewith and being movablerelative to said bar into and out of engagement with said support.

3. The combination with an ingot stripping apparatus; of a mold supportmounted for movements with respect to said apparatus for positioning amold in stripping position relative to said apparatus; a bar mounted forlongitudinal movement in the direction of travel of said support; meansoperatively connected to said bar for reciprocating the latter; a pawlpivotally mounted on said bar and having its nose movable into en'-gagement with said support for effecting driving connection between saidbar and said support; and control means operatively connected to saidpawl for moving the latter into and out of en-- gagement with saidsupport.

4. The combination with an ingot stripping apparatus; of a mold supportmounted for movements with respect to said apparatus for positioning amold in stripping position relative to said apparatus; a bar mounted forlongitudinal movement in the direction of travel of said support; meansoperatively connected to said bar for reciprocating the latter; a pawlpivotally mounted on said bar and having its nose movable intoengagement with said support; means operatively connected to said pawlfor urging the latterinto operative position with its nose engaging saidsupport; a control device; and means providing operative connectionbetween said device and said pawl irrespective of the position of saidbar for moving the pawl to disengage its nose from said support.

5. The combination with an ingot stripping apparatus; of a mold supportmounted for move ments with respect to said apparatus for positioning amold in stripping position relative to said apparatus; a bar mounted forlongitudinal movement in the direction of travel of said support; meansoperatively connected to said bar for reciprocating the latter; a pawlpivotally mounted on said bar and having its nose movable intoengagement with said support; means operatively connected to said pawlfor urging the latter into operative position with its nose engagingsaid support; a control device; means providing operative connectionbetween said device and said pawl irrespective of the position of saidbar for moving the pawl to disengage its nose from said support; andmeans on said bar for locking said pawl in operative position.

6. The combination with an ingot stripping apparatus; of a mold supportmounted for movements with respect to said apparatus for positioning amold in stripping position relative to said apparatus; a bar mounted forlongitudinal movement in the direction of travel of said support; meansoperatively connected to said bar for reciprocating the latter; a pawlpivotally mounted on said bar and having its nose movable intoengagement with said support; means operatively connected to said pawlfor urging the latter into operative position with its nose engagingsaid support; a rail extending parallel and adjacent to said bar; andmeans mounting said rail for movements with respect to the bar and intoengagement with said pawl for moving the latter to inoperative position.

7. The combination with an ingot stripping apparatus; of a mold supportmounted for movements with respect to said apparatus for positioning amold in stripping position relative to said apparatus; a bar mounted forlongitudinal movement in the direction of travel of said support; meansoperatively connected to said bar for reciprocating the latter; a pawlpivotally mounted on said bar and having its nose movable intoengagement with said support; means operatively connected to said pawlfor urging the latter into operative position with its nose engagingsaid support; a rail extending parallel and adjacent to said bar; a pairof spaced parallel levers pivotally connected to said rail; and meansfor rocking one of said levers to move said rail into engagement withsaid pawl.

8, The combination with an ingot stripping apparatus; of a mold supportmounted for movements with respect to said apparatus for positioning amold in stripping position relative to said apparatus; a bar mounted forlongitudinal movement in the direction of travel of said support: meansoperatively connected to said barfor reciprocating the latter; a pawlpivotally mounted on said bar and having its nose movable intoengagement with said support; means operatively connected to said pawlfor urging the latter into operative position with its nose engagingsaid support; a latch pivotally connected to said bar and being movableinto engagement with said pawl for locking the latter in operativeposition; a rail extending parallel and adjacent to said bar; and meansmounting said rail for movements with respect to the bar and intoengagement with said pawl and said latch for moving both to inoperativepositions.

9. The combination with an ingot stripping apparatus; of a moldsupporting car mounted for movements with respect to said apparatus forpositioning a mold in stripping position relative to said apparatus; arack bar mounted for longitudinal movements in the direction of travelof said car; a motor having driving connection with said rack bar foroperating the latter in both directions; and means mounted on said rackbar for .movements with the latter and also being movable relativethereto into engagement with said car for effecting driving connectionbetween said rack bar and said car and being also movable out ofengagement with said car.

10. The combination with an ingot stripping apparatus; of a moldsupporting car mounted for movements with respect to said apparatus forpositioning a mold in stripping position relative to said apparatus; arack bar mounted for longitudinal movements in the direction of travelof said car; a motor having driving connection with said rack bar foroperating the latter in both directions; a pawl pivotally mounted onsaid rack bar and having its nose movable with the latter and also beingmovable relative thereto into and out of engagement with said car; meansoperatively connected to said pawl for urging the latter into operativeposition with its nose in engagement with said car; a rail extendingparallel and adjacent, to said rack bar; and means mounting said railfor movements with respect to said rack bar and into engagement withsaid pawl irrespective of the position of the rack bar for moving thepawl to inoperative position. 1

11. The combination with an ingot stripping apparatus; of a moldsupporting car mounted for movements with respect to said apparatus forpositioning a mold in stripping position relative to said apparatus; arack bar mounted for longitudinal movements in the direction of travelof said car; a motor having driving connection with said rack bar foroperating the latter in both directions; a pawl pivotally mounted onsaid rack bar and having its nose movable with the latter and also beingmovable relative thereto into and out of engagement with said car; meansoperatively connected to said pawl for urging the latter into operativeposition with its nose in engagement with said car; a latch pivotallyconnected to said rack bar and being movable into engagement with saidpawl for locking the latter in operative position; a rail extendingparallel to said bar; and means mounting said rail for movements intoengagement with said pawl and said latch irrespective of the position ofthe rack bar for moving said pawl and latch to inoperative positions.

12. The combination with an ingot stripping apparatus; of a mold supportmounted for movements with respect to the apparatus for positioning amold in stripping position relative to said apparatus; driving means formoving said mold support to place a supported mold in strippingposition; and control means responsive to movement of said mold supportfor automatically arresting movement of said mold support when saidsupported mold has been moved to stripping position.

13. The combination with an ingot stripping apparatus; of a mold supportmounted for movements with respect to the apparatus for positioning amold in stripping position relative to said apparatus; a stationarymotor; means for transmitting drive from said motor to said mold supportfor moving the latter to place a supported mold in stripping position;and control means for said motor operable automatically by engagement bysaid support when said supported mold has reached stripping position forarresting operation of said motor.

14. The combination with an ingot stripping apparatus; of a mold supportmounted for movements with respect to the apparatus for positioning amold in stripping position relative to said apparatus; an electricmotor; means for transmitting drive from said motor to said mold supportfor moving the latter to place a supported mold in stripping position; amotor stopping limit switch in circuit with said motor; and meansoperable when said supported mold has reached stripping position forautomatically operating said limit switch to stop operation of themotor.

15. The combination with an ingot stripping apparatus; of a mold supportmounted for movements with respect to the apparatus for positioning amold in stripping position relative to said apparatus; an electricmotor; means for transmitting drive from said motor to said mold supportfor moving the latter to place a supported mold in stripping position; amotor stopping limit switch for controlling operation of said motor; andmeans connected to said switch and being engageable by said support whensaid supported mold has reached stripping position for operating saidswitch to arrest operation of the motor.

16. The combination with an ingot stripping apparatus; of a mold supportmounted for movements with respect to said apparatus for positioningsuccessively a plurality of molds carried by the support in strippingposition relative to said apparatus; an electric motor having drivingconnection with said mold support for moving the latter; a motorstopping limit switch for controlling operation of said motor; meansconnected to said switch and being engageable by said support when amold has reached stripping position for operating said switch to arrestoperation of the motor; and a second switch for controlling operation ofsaid motor independently of said limit switch.

1'7. The combination with an ingot stripping to said apparatus; anelectric motor having driving connection with said mold support formoving the latter; a limit switch for controlling operation of saidmotor; means connected to said switch and being engageable by saidsupport when a mold has reached stripping position for operating saidswitch to arrest operation of the motor; and a manually operable switchconnected across said limit switch.

18. The combination with an ingot stripping apparatus; of a mold supportmounted for movements with respect to said apparatus for positioningsuccessively a plurality of molds carried by the support in strippingposition relative to said apparatus; a rack bar connected to saidsupport for moving the latter; an electric motor having drivingconnection with said rack bar for operating the latter; a motor stoppinglimit switch for controlling operation of said motor; means connected tosaid switch and being engageable by said support when a mold has reachedstripping position for operating said switch to arrest operation of themotor; and a second switch for controlling operation of said motorindependently of said limit switch. 7

19. The combination with an ingot stripping apparatus; of a mold supportmounted for movements with respect to said apparatus for positioningsuccessively a plurality of molds carried by the support in strippingposition relative to said apparatus; a rack bar connected to saidsupport for moving the latter; an electric motor having drivingconnection with said rack bar for operating the latter; a motor stoppinglimit switch for controlling operation of said motor; means connected tosaid switch and being engageable by said support when a mold has reachedstripping position for operating said switch to arrest operation of themotor; and other motor stopping limit switch means in circuit with saidmotor and being engageable by said rack when the latter approaches theend of its travel for stopping said motor to prevent over travel of saidrack bar.

20. The combination with an ingot stripping apparatus; of a mold supportmounted for movements with respect to said apparatusfor positioningsuccessively a plurality of molds carried by the support in strippingposition relative to said apparatus; an electric motor having drivingconnection with said mold support for moving the latter; a motorstopping limit switch for controlling operation of said motor; aplurality of projections on said support, one opposite each moldsupported thereby; means connected to said switch and being engageableby said projections individually when the associated molds have reachedstripping position for operating said switch to arrest operation of themotor; and a second switch for controlling operation of said motorindependently of said limit switch.

21. A device for holding ingot molds against movement during strippingof ingots therefrom comprising a head including a body member; a pair ofspaced substantially parallel mold-engaging legs mounted on said bodyfor movements towards and from each other; and means operativelyconnecting said legs and being operable to vary the distance between thelegs to adapt the latter for engagement with molds of different sizes.

22. A device for holding ingot molds against movement during strippingof ingots therefrom comprising a head including a body member; a pair ofspaced substantially parallel mold-engaging legs slidably mounted onsaid body for movements towards and from each other; and a captive screwmounted on said body for rotary movements and having threaded connectionwith said legs.

23. In apparatus for stripping an ingot from an ingot mold, thecombination of a mold support; a holding device mounted for movementinto engagement with a mold in stripping position on said support; meansoperatively connected to said holding device for driving the latter intomold-engaging position; and control means operatively connected withsaid driving means and being responsive to engagement of said hold downdevice with said mold for automatically stopping operation of saiddriving means.

24. In apparatus for stripping an ingot from an ingot mold, thecombination of a mold support; a holding device mounted for movementinto engagement with a mold in stripping position on said support; amotor having driving connection with said holding device for moving thelatter into mold-engaging position; and control means operativelyconnected with said motor and being carried by said holding device andbeing responsive-to engagement of said holding device with said mold forautomatically stopping operation of said motor.

25. In apparatus for stripping an ingot from an ingot mold, thecombination of a mold support; a screw mounted for movements parallel tothe axis of a mold in stripping position on said support; a head on saidscrew engageable with said mold; a captive nut having threadedengagement with said screw for operating the latter; an electric motorhaving driving connection with said nut; and means including a motorstopping switch in circuit with said motor, said means being responsiveto engagement of said head with said mold for stopping said motor.

26. In apparatus for stripping an ingot from an ingot mold, thecombination of a mold support; a screw mounted for movements parallel tothe axis of a mold in stripping position on said support; amold-engaging head mounted on said screw and having lost motionconnection therewith; a captive nut having threaded connection with saidscrew for operating the latter; an electric motor having drivingconnection with said nut; a motor stopping switch in circuit. with saidmotor and being mounted on said screw; and a connection between saidhead and said switch for operating the latter to stop said motor whensaid head engages the mold on said support and relative movement of saidhead and screw is produced.

27. In apparatus for stripping an ingot from an ingot mold, thecombination of a mold support; a driven member mounted for movementstowards and from said support; a mold-engaging head loosely mounted onsaid driven member for limited movement relative to said member in thedirection of travel of the latter; an electric motor having drivingconnection with said driven member for operating the latter; a motorstopping switch carried by said driven member and in circuit with saidmotor for controlling operation thereof; and a rod carried by saidmember extending longitudinally thereof and having one of its ends inengagement with said molden'gaging head and its other end disposed forengagement with said switch for operating thev latter to stop said motorwhen said head engages a mold in stripping'position on said support.

28. In apparatus for stripping an ingot from an ingot mold, thecombination of a mold support; a screw mounted for vertical movementsabove said support; a mold-engaging head mounted on the lower end ofsaid screw for limited movements relative to the screw in the line oftravel of the latter; an electric motor having driving connection withsaid screw; a stop switch mounted on the upper end of said screw andbeing con nected in circuit with said motor; and a rod extendinglongitudinally through said screw, the.

operatively connected with said driving means and being responsive toengagement of said holding device with said mold for automaticallystopping operation of said driving means; and other control meansindependent of said first named control means for limiting the totaltravel of said holding device.

30. In apparatus for stripping an ingot from an ingot mold, thecombination of a mold support; a screw mounted for vertical movementsabove said support; a mold-engaging head mounted on the lower end ofsaid screw for limited movements relative to said screw in the line oftravel of the latter; an electric motor having driving connection withsaid screw; a stop switch mounted on the upper end of said screw andbeing connected in circuit with said motor; a rod extendinglongitudinally through said screw, the lower end of the rod being inengagement with said head and the upper end of the rod being adapted toengage and operate said stop switch when the head engages a mold on saidsupport; and limit switch means in circuit with said motor and operableby said screw when. the latter approaches the limit of its travel forpreventing over travel thereof.

31. In apparatus for stripping an ingot from an ingot mold, thecombination of a mold support; a screw mounted for vertical movementsabove said support; a mold-engaging head mounted on the lower end ofsaid screw for limited movements relative to the screw in the line oftravel of the latter; an electric motor having driving connectionwith'said screw; means including a stop switch mounted on the upper endof said screw and being connected in circuit with 'said motor foreffecting operation of said motor in a direction to drive said screwdownwardly; a rod extending longitudinally through said screw, the lowerend of the rod'being in engagement with said head and the upper end ofthe rod being adapted to engage and operate said stop switch when thehead engages a mold on said support; and means including a switch forclosing a circuit through said motor for efiecting operation of saidmotor in the opposite direction to drive said screw upwardlyindependently of said stop switch.

32. In apparatus for stripping an ingot from an ingot mold, thecombination of a mold support; a screw mounted for vertical movementsabove said support; a mold-engaging head mounted on the lower end ofsaid screw for limited movements relative to the screw in the line oftravel of the latter; an electric motor having driving connection withsaid screw; a stop switch mounted on the upper end of said screw incircuit with said motor; a rod extending longitudinally through saidscrew, the lower end of the rod being in engagement with said head andthe upper end of the rod being adapted to engage and operate said stopswitch when the head engages a mold on said support; limit switch meansin circuit with said motor and operable by said screw when the latterapproaches the limit of its travel for preventing over travel thereof;and other switch means for closing a circuit through said motorindependently of said stop switch and said limit switch means.

33. In apparatus for stripping an ingot from an ingot mold, thecombination of a mold support; means for holding a mold on said support;an ingot stripping device associated with said holding means; poweroperated means engageable with said stripping device for operating thelatter; means for supplying power to said power operated means; andcontrol means responsive to resistance due to sticking of the ingot inthe mold for automatically supplying increased power to overcome suchsticking resistance.

34. In apparatus for stripping an ingot from an ingot mold, thecombination of a mold support; means for holding a mold on said support;an ingot stripping device associated with said holding means; ahydraulically actuated plunger engageable with said stripping device foroperating the latter; means for supplying fluid under pressure to saidplunger; and means responsive to resistance due to sticking of the ingoton the mold for automatically supplying fluid to said plunger underincreased pressure to overcome such sticking resistance.

35. In apparatus for stripping an ingot from an ingot mold, thecombination of a mold support; means for holding a mold on said support;an ingot stripping device associated with said holding means; ahydraulic plunger engageable with said stripping device for operatingthe latter; a pump having a predetermined maximum discharge pressure; apipe line for delivering fluid under pressure from said pump to saidplunger; 8. second pump having a predetermined maximum dischargepressure higher than that of said first pump; a pipe line for deliveringfluid under pressure from said second pump to' said plunger; a checkvalve in said first pipe line arranged to permit flow therethrough in adirection away from said first pump but not in the opposite direction;and means operatively connected to said pumps for driving the latter.

36. In apparatus for stripping an ingot from an ingot mold,thecombination of a mold support; means for holding a mold on saidsupport; an ingot stripping device associated with said holding means; ahydraulic plunger engageable with said stripping device for operatingthe latter; a low pressure pump having a high rate of discharge; a pipeline for delivering fluid under pressure from said pump to said plunger;a high pressure pump having a low rate of discharge; a pipe line fordelivering fluid under pressure from said second pump to said plunger; acheck valve in said first pipe line arranged to permit flow therethroughin a direction away from said first pump but not in the oppositedirection; and means operatively connected to said pumps for operatingthe latter.

37. In apparatus for stripping an ingot from an ingot mold, thecombination of a mold support; means for holding a mold on said support;

an ingot stripping device associated with said holding means; acylinder; a hydraulic plunger therein engageable with said strippingdevice for operating the latter; a pump; a pipe line for supplying fiuidunder pressure from said pump to said cylinder; a fluid exhaust;electrically actuated valve means connected in said pipe line forplacing said cylinder in communication with said pump or said exhaust;and means including a switch in circuit with said electrically actu-'ated valve means, said means being responsive to movement of saidplunger during a stripping operation for effecting operation of saidvalve means to place said cylinder in communication with said exhaust.

38. In apparatus for. stripping an ingot from an ingot mold, thecombination of a mold support; means for holding a mold down on saidsupport; a vertically movable stripper rod associated with said supportand holding means; a hydraulic cylinder mounted underneath andsubstantially coaxial with saidstripper rod; a hydraulic plunger thereinengageable with said stripper rod for operating the latter; means forsupplying fluid under pressure to said cylinder; electrically actuatedmeans for controlling the supply of fluid to said cylinder; a switch incircuit with said means and mounted in fixed relation to said cylinder;and an apron connected to said plunger and being engageable with saidswitch for operating the latter during a stripping operation to effectactuation of said control means and stopping of supply of fluid to saidcylinder.

39. In apparatus for stripping ingots from ingot molds, the combinationof a movable mold support; a mold holding device mounted for movementsinto mold-engaging position; driving means for operating said moldsupport to position a supported mold in stripping position relative tosaid apparatus; and control means associated with said driving means andbeing responsive to engagement of the mold holding device with said moldfor preventing operation of said driving means.

40. In apparatus for stripping ingots from ingotmolds, the combinationoi a movable mold support; a mold holding device mounted for movementsinto mold-engaging position; an electric motor having driving connectionwith said mold support for moving the latter to position a supportedmold in stripping position relative to said apparatus; a switch incircuit with said motor; and means .operatively connected to said switchand being responsive to engagement oi said holding device with said moldfor operatng said switch to prevent operation of said motor.

41. In apparatus for stripping ingots from ingot molds, the combinationof a movable mold support; a mold holding device mounted for movementsinto mold-engaging position; driving means for operatingsaid moldsupport to position a supported mold in stripping position relative tosaid apparatus; driving means oper'atively connected to said holdingdevice for operating the latter into mold-engaging position; and controlmeans operatively connected to said driving means and being responsiveto engagement of the mold holding device with the mold for preventingoperation of both of said driving means.

42. In apparatus for stripping ingots from ingot molds, the combinationof a reciprocable stripper plunger; a movable mold support; drivingmeans operatively connected with said support for moving the latter toposition a supported mold adjacent said plunger in stripping postion;

